Expandable intervertebral spacer

What is claimed is: 
     
         1 . A device for facilitating a spinal fusion procedure comprising:
 an anterior spacer;   a posterior spacer;   a first lateral spacer;   a second lateral spacer; and   first, second, third, and fourth hinge members, wherein the first hinge member extends between and is rotatably coupled with the anterior spacer and the first lateral spacer, wherein the second hinge member extends between and is rotatably coupled with the first lateral spacer and the posterior spacer, wherein the third hinge member extends between and is rotatably coupled with the posterior spacer and the second lateral spacer, wherein the fourth hinge member extends between and is rotatably coupled with the anterior spacer and second lateral spacer.   
     
     
         2 . The device of  claim 1 , further comprising an actuator extending between the anterior spacer and the posterior spacer, wherein actuation of the actuator in a first direction moves the anterior and posterior spacers away from one another to place the device in a collapsed configuration and actuation of the actuator in a second direction moves the anterior and posterior spacers toward one another to place the device in an expanded or partially expanded configuration. 
     
     
         3 . The device of  claim 2 , wherein the actuator is a rod extending between the anterior and posterior spacers and adapted to rotate with respect to the device, wherein the anterior or posterior space comprises a threaded opening, wherein at least a portion of the rod comprises screw threads along a distal portion of the rod, wherein the screw thread engage the threaded opening, and wherein rotation of the rod in the first direction draws the anterior and posterior spacers toward one another. 
     
     
         4 . The device of  claim 3 , wherein the anterior or posterior spacer further comprises a threaded sleeve forming a portion of the threaded opening. 
     
     
         5 . The device of  claim 2 , wherein, in the collapsed configuration a lateral distance defined by the lateral spacers is adapted for delivery through an endoscope or working tube. 
     
     
         6 . The device of  claim 2 , wherein, in the expanded or partially expanded configuration, one or more of the anterior spacer, posterior spacer, and lateral spacers are adapted to be placed between cortical bony rims of the endplates of adjacent vertebrae in an MIS procedure. 
     
     
         7 . The device of  claim 3 , wherein the rod includes a tool engagement at an end of the rod opposite the screw threads, wherein the tool engagement is adapted to be coupled with a tool for rotation of the rod to actuate the actuator. 
     
     
         8 . The device of  claim 7 , further comprising a screw plate, wherein the screw plate includes one or more bone screw apertures, wherein the screw plate is adapted to be connected with the anterior or posterior spacer. 
     
     
         9 . The device of  claim 8 , wherein the screw plate further comprises a locking protrusion, wherein, when the screw plate is engaged with the anterior or posterior spacer, the locking protrusion engages with the tool engagement to prevent rotation of the rod. 
     
     
         10 . The device of  claim 8 , wherein the screw plate comprises one or more bone screw apertures, wherein the apertures are adapted to hold a respective bone screw, and wherein the bone screws are adapted to connect the device with adjacent vertebrae using MIS techniques. 
     
     
         11 . The device of  claim 1 , wherein one or more surfaces of the anterior, posterior, and lateral spacers comprise a surface coating or surface texture, and wherein the coating or texture is adapted to facilitate ongrowth of bone tissue. 
     
     
         12 . The device of  claim 1 , wherein the anterior spacer includes a receiving channel having a retention feature. 
     
     
         13 . The device of  claim 12 , further comprising a bone staple having at least two piercing members and a securing member disposed between the piercing members, and wherein the securing member is adapted to engage with the receiving channel, and wherein the securing member includes at least one flexible projection configured to engage with the at least one retention feature. 
     
     
         14 . A device for facilitating a spinal fusion procedure comprising:
 a plurality of spacers;   a central hub; and   a plurality of hinge members, wherein respective ones of the hinge members rotatably couple respective ones of the spacers with the central hub, and wherein the spacers are adapted to be positioned with respect to adjacent vertebrae during the procedure by rotating the respective hinge member relative to the hub.   
     
     
         15 . The device of  claim 14 , wherein the plurality of spacers comprise:
 an anterior spacer;   a posterior spacer;   a first lateral spacer; and   a second lateral spacer.   
     
     
         16 . The device of  claim 14 , wherein one or more of the plurality of hinge members is extendable to a selected length. 
     
     
         17 . The device of  claim 16 , wherein the extendable hinge member comprises a locking mechanism, wherein the length of the hinge member is adapted to be locked to the respective spacer between cortical bony rims of endplates of the adjacent vertebrae.